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ISC'11 Japan needs a little good news these days, and it comes from the International Super Computing 2011 conference in Hamburg, Germany, as the K supercomputer, a massively parallel Sparc-based cluster built by Fujitsu, has taken the lead in the number-crunching race as gauged by the June 2011 edition of the Top 500 supercomputer list and its Linpack Fortran benchmark.

The K machine was developed under the Project Keisoku name and was sometimes called the Next Generation Supercomputer Project as it was under development by the Japanese government. The machine was slated to cost $1.2bn and was to have a hybrid architecture featuring the three system titans of Japan, with vector machines and interconnect designed by NEC and Hitachi and scalar machines created by Fujitsu, with a combined peak performance of 10 petaflops. In May 2009, citing the excessive costs of production at the same time the Great Recession hit, NEC and Hitachi pulled out of the project, leaving Fujitsu holding the K football and having to keep the project alive and transition it to a Sparc-only design as it took it into the political end zone for continued funding.

The K supercomputer at Riken

As El Reg detailed last fall, Fujitsu kept the 6D mesh torus interconnect that was created by the three vendors for the K machine and simply built the whole box using its four-socket, water-cooled blade servers instead of a mix of vector and scalar processors. Fujitsu created the eight-core "Venus" Sparc64-VIIIfx chip specifically for the machine, and neither Oracle nor Fujitsu has committed to using this processor in commercial Sparc Enterprise M servers. (And they are damned fools if they don't.) The processors run at 2GHz, and each blade has 512 gigaflops of double-precision floating point power, which is not a lot for a GPU but it is not too bad for a CPU. The K super is located at the Rikagaku Kenkyusho (Riken) research lab in Kobe, Japan. The current configuration of the K machine has 548,352 cores – that's 17,136 blade servers – for a total of 8.77 peak petaflops. And here's the cool bit: running the Fortran matrix test and using that Tofu interconnect, the machine was able to actually crank through 8.16 petaflops, yielding a "shut your mouth" 93 per cent efficiency.

Maybe NEC and Hitachi were perhaps a little hasty?

One K super and Sparc is now a big part of the aggregate Top 500 oomph

The K super quite handily dispatched the former champ, which only held the title for half a year. That was the Tianhe-1A hybrid super at the National Supercomputing Center in Tianjin. The Tianhe-1A mixes six-core Intel Xeon processors, Nvidia Tesla GPUs, and a smattering of homegrown Sparc processors (yes, China makes its own Sparc chips) to hit 2.56 petaflops. The Tianhe-1A ceepie-geepie has 14,336 Xeon processors and 7,168 of Nvidia's Tesla M2050 fanless GPU coprocessors, and uses a homegrown tray server design and a proprietary interconnect called Arch; it has 186,368 cores across those CPUs and GPUs, the latter of which link into the CPUs through PCI-Express peripheral slots. While the Tianhe-1A machine has a peak theoretical performance of 4.7 petaflops, the resulting machine has only a 54.6 per cent efficiency running the Linpack test.

Riken says the K super consumed 9.89 megawatts of juice. The Tianhe-1A machine only draws 4 megawatts, so even if it is a lot less efficient, the performance per watt of these two machines is a lot closer than you might think. We'll save the thermal efficiency analysis for the Top 500 list for another day, but suffice it to say that there are 29 machines on the June 2011 list that burn more than 1 megawatt.

Japan and China each have another system in the top ten portion of the list.

China holds the number four position with "Nebulae" machine, another ceepie-geepie comprised of Xeon processors and Nvidia Teslas, that is installed at the National Supercomputing Center in Shenzhen. The Nebulae machine has a total of 120,640 cores across its CPUs and GPUs, which are housed in a blade server chassis crafted by Chinese server maker Dawning. This machine has a peak performance of 2.98 petaflops, but only hits 1.27 petaflops where the Fortran compiler hits the silicon.

Japan's other system at the top portion of the June 2011 supers ranking is the Tsubame 2.0 super, which is built from Hewlett-Packard's ProLiant SL390s G7 tray servers, sporting Xeons and Nvidia Tesla coprocessors. NEC is prime contractor on this machine, even though the components come from American IT companies, which is politically necessary to have the machine installed at the Tokyo Institute of Technology. This hybrid super has a total of 73,278 cores and a peak performance of 2.29 petaflops, but like other ceepie-geepies, the efficiency is low running Linpack and only 1.19 petaflops actually gets done doing the benchmark.

The top machine in the United States is the "Jaguar" supercomputer installed at Oak Ridge National Laboratory, which was ranked first in the world on the November 2009 and June 2010 lists, but which was knocked into the number two spot by Tianhe-1A last November. Jaguar is a Cray XT5 system based on six-core Opteron processors from AMD and uses the SeaStar-2+ interconnect. This machine is a bit long in the tooth and should be updated to 16-core Opterons and the "Gemini" XE6 interconnect if the US Department of Energy wants to spend the dough. Jaguar has 224,162 Opteron cores and is rated at 1.76 petaflops on the Linpack test at an efficiency of about 75.5 per cent.